Parts of the Brain - Memory & the Brain - The Human Memory MEMORY & THE BRAIN Neurons & Synapses PARTS OF THE BRAIN The human brain is hugely interconnected but three major components can be identified: the cerebrum, the cerebellum and the brain stem. The brainstem which includes the medulla, the pons and the midbrain, controls breathing, digestion, heart rate and other autonomic processes, as well as connecting the brain with the spinal cord and the rest of the body. The cerebellum plays an important role in balance, motor control, but is also involved in some cognitive functions such as attention, language, emotional functions (such as regulating fear and pleasure responses) and in the processing of procedural memories . The cerebrum (or forebrain), which makes up 75% of the brain by volume and 85% by weight, is divided by a large groove, known as the longitudinal fissure, into two distinct hemispheres.

The left and right hemispheres ("left" and "right" refer to the owner's point of view, not an outside viewer's) are linked by a large bundle of nerve fibres called the corpus callosum, and also by other smaller connections called commissures. Most of the important elements of the cerebrum, are split into symmetrical pairs in the left and right hemispheres. Thus, we often speak of the temporal lobes, hippocampi, etc (in the plural), although this website generally follows the convention of speaking of the temporal lobe, hippocampus, etc (in the singular), which should therefore be taken to mean both sides, within both hemispheres. The two hemispheres look similar, but are slightly different in structure and perform different functions. The right hemisphere generally controls the left side of the body, and vice versa, although popular notions that logic, creativity, etc, are restricted to the left or right hemispheres are largely simplistic and unfounded.

Lobes of the cerebral cortex Picture from Wikipedia ( The cerebrum is covered by a sheet of neural tissue known as the cerebral cortex (or neocortex), which envelops other brain organs such as the thalamus (which evolved to help relay information from the brain stem and spinal cord to the cerebral cortex) and the hypothalamus and pituitary gland (which control visceral functions, body temperature and behavioural responses such as feeding, drinking, sexual response, aggression and pleasure). The cerebral cortex itself is only 2 - 4 mm thick, and contains six distinct but interconnected layers. It is intricately grooved and folded into the familiar convoluted pattern of folds, or gyri, allowing a large surface area (typically almost 2m2) to fit within the confines of the skull. Consequently, more than two-thirds of the cerebral cortex is buried in the grooves, or sulci. About 90% of all the brain�s neurons are located in the cerebral cortex, mainly in the "grey matter", which makes up the surface regions of the cerebral cortex, while the inner "white matter" consists mainly of myelinated axons, over 170,000 km of them.

As many as five times that number of glial cells exist to support the active nerve cells. The cerebral cortex plays a key role in memory, attention, perceptual awareness, thought, language and consciousness. It is divided into four main regions or lobes, which cover both hemispheres: the frontal lobe (involved in conscious thought and higher mental functions such as decision-making, particularly in that part of the frontal lobe known as the prefrontal cortex, and plays an important part in processing short-term memories and retaining longer term memories which are not task-based); the parietal lobe (involved in integrating sensory information from the various senses, and in the manipulation of objects in determining spatial sense and navigation); the temporal lobe (involved with the senses of smell and sound, the processing of semantics in both speech and vision, including the processing of complex stimuli like faces and scenes, and plays a key role in the formation of long-term memory ); and the occipital lobe (mainly involved with the sense of sight).

The Limbic System and Basal Ganglia Picture from How Stuff Works ( swearing.htm/printable) The medial temporal lobe (the inner part of the temporal lobe, near the divide between the left and right hemispheres) in particular is thought to be involved in declarative and episodic memory . Deep inside the medial temporal lobe is the region of the brain known as the limbic system, which includes the hippocampus, the amygdala, the cingulate gyrus, the thalamus, the hypothalamus, the epithalamus, the mammillary body and other organs, many of which are of particular relevance to the processing of memory. The hippocampus, for example, is essential for memory function, particularly the transference from short- to long-term memory and control of spatial memory and behaviour. The hippocampus is one of the few areas of the brain capable actually growing new neurons , although this ability is impaired by stress-related glucocorticoids. The amygdala also performs a primary role in the processing and memory of emotional reactions and social and sexual behaviour, as well as regulating the sense of smell.

Another sub-cortical systems (inside the cerebral cortex) which is essential to memory function is the basal ganglia system, particularly the striatum (or neostriatum) which is important in the formation and retrieval of procedural memory . Brain Regions IMPORTANT BRAIN REGIONS RELATED TO COGNITION: Amygdala: Responsible for emotional integration of sensory input and memories. Basal ganglia: Located deep in the hemispheres. The basal ganglia are made up of the globus pallidus, caudate nucleus, and amygdala. Forms a circuit with the cortex. Important in the regulation of movement and in habit learning. Works closely with the frontal lobes. Brain stem: Connection from the spinal cord to lower areas of the brain. Responsible for autonomic functions such as heart rate, blood pressure, and the like. Motor and sensory neurons pass through the brain stem. Broca’s area: Located in the left frontal lobe. Involved in the production of fluent speech. Caudate nucleus: Part of the neostriatum, which is part of basal ganglia.

Receives projections from the neocortex and connects through the putamen and globus pallidus to the thalamus and finally to the motor area of the cortex. Cerebellum: The back portion of the brain that assists in coordinating movement. Damage often results in ataxia (uncoordinated voluntary muscle movements). Cerebrum: The largest part of the brain, divided into the left and right cerebral hemispheres. These upper portions of the brain are believed to be predominantly responsible for higher-order functions. Divided into the left and right cerebral hemispheres. Left cerebral hemisphere: In most people the left cerebral hemisphere is responsible for speech, math, reading, and writing. Damage to the left hemisphere often results in problems with verbal communication and problems with movement on the right side of the body. Right cerebral hemisphere: In most people the right cerebral hemisphere is responsible for visuospatial skills, direction, attention, and the regulation of emotions. Damage to this area will affect movement on the left side of the body and visuospatial abilities. Corpus callosum: Connects the two hemispheres of the brain, allowing for communication between them.

Frontal lobes: Responsible for higher-order functioning (judgment, abstraction, and motivation) and the production of speech and has influence on personality. Damage results in difficulty with verbal expression, difficulty concentrating, and lack of emotional control. In the back of the frontal lobes are the motor areas that control voluntary movements. Damage results in contralateral paralysis, or paralysis on the opposite side of the body. Hippocampus: Structure in the brain believed to be responsible for the processing and coordination of memory functioning. It is the end point of the cortex and the ultimate destination of multiple cortical and subcortical processes. Neurons: Cells in the brain that store and process information. Neurotransmitters: Chemicals produced by the neurons that carry information from neuron to neuron. Specific neurotransmitters are responsible for specific tasks (for instance, dopamine is responsible for movement). Occipital lobes: Located in the back of the brain. Responsible for regulation and processing of sight Parietal lobes: The anterior (front part) of the parietal lobes is responsible for tactile discrimination and recognition. The posterior (back part) of the parietal lobe is responsible for attention.

The left parietal lobe is responsible for reading, writing, arithmetic, and The Mild Traumatic Brain Injury Workbook performance of learned information. Its other function is speech. The right parietal lobe is responsible for the comprehension of visuospatial relationships and understanding facial expressions and tones in speech. Substantia nigra: Connects basal ganglia to the midbrain. Provides dopamine to the Temporal lobes: Important for memory. When information enters the sensory registers it is briefly stored here and then sent to long-term memory or lost. The bottom section (ventral portion) of the temporal lobes regulates the recognition of faces and objects (note that this is a different function than recognizing facial expressions). The left portion of the temporal lobe is important for processing auditory information. Thalamus: Responsible for the relay of sensory information. Coordinates information with the temporal lobes and serves a primary function in memory. Wernicke’s area: Located in the rear of the superior temporal gyrus. Believed to be involved in the comprehension of speech. Copyright © 2003 - 2006, The Memory Doctor, LLC. All Rights Reserved.

Brain Structures and Their Functions Brain Structures and their Functions Brain Stem The nervous system is your body's decision and communication center. The central nervous system (CNS) is made of the brain and the spinal cord and the peripheral nervous system (PNS) is made of nerves. Together they control every part of your daily life, from breathing and blinking to helping you memorize facts for a test. Nerves reach from your brain to your face, ears, eyes, nose, and spinal cord... and from the spinal cord to the rest of your body. Sensory nerves gather information from the environment, send that info to the spinal cord, which then speed the message to the brain. The brain then makes sense of that message and fires off a response. Motor neurons deliver the instructions from the brain to the rest of your body. The spinal cord, made of a bundle of nerves running up and down the spine, is similar to a superhighway, speeding messages to and from the brain at every second. The brain is made of three main parts: the forebrain, midbrain, and hindbrain. The forebrain consists of the cerebrum, thalamus, and hypothalamus (part of the limbic system).

The midbrain consists of the tectum and tegmentum. The hindbrain is made of the cerebellum, pons and medulla. Often the midbrain, pons, and medulla are referred to together as the brainstem. The Cerebrum: The cerebrum or cortex is the largest part of the human brain, associated with higher brain function such as thought and action. The cerebral cortex is divided into four sections, called "lobes": the frontal lobe, parietal lobe, occipital lobe, and temporal lobe. Here is a visual representation of the cortex: What do each of these lobes do? Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Occipital Lobe- associated with visual processing Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech Note that the cerebral cortex is highly wrinkled. Essentially this makes the brain more efficient, because it can increase the surface area of the brain and the amount of neurons within it.

We will discuss the relevance of the degree of cortical folding (or gyrencephalization) later. (Go here for more information about cortical folding) A deep furrow divides the cerebrum into two halves, known as the left and right hemispheres. The two hemispheres look mostly symmetrical yet it has been shown that each side functions slightly different than the other. Sometimes the right hemisphere is associated with creativity and the left hemispheres is associated with logic abilities. The corpus callosum is a bundle of axons which connects these two hemispheres. Nerve cells make up the gray surface of the cerebrum which is a little thicker than your thumb. White nerve fibers underneath carry signals between the nerve cells and other parts of the brain and body. The neocortex occupies the bulk of the cerebrum. This is a six-layered structure of the cerebral cortex which is only found in mammals. It is thought that the neocortex is a recently evolved structure, and is associated with "higher" information processing by more fully evolved animals (such as humans, primates, dolphins, etc). For more information about the neocortex, click here .

The Cerebellum: The cerebellum, or "little brain", is similar to the cerebrum in that it has two hemispheres and has a highly folded surface or cortex. This structure is associated with regulation and coordination of movement, posture, and balance. The cerebellum is assumed to be much older than the cerebrum, evolutionarily. What do I mean by this? In other words, animals which scientists assume to have evolved prior to humans, for example reptiles, do have developed cerebellums. However, reptiles do not have neocortex. Go here for more discussion of the neocortex or go to the following web site for a more detailed look at evolution of brain structures and intelligence: "Ask the Experts": Evolution and Intelligence Limbic System: The limbic system, often referred to as the "emotional brain", is found buried within the cerebrum. Like the cerebellum, evolutionarily the structure is rather old. This system contains the thalamus, hypothalamus, amygdala, and hippocampus.

Here is a visual representation of this system, from a midsagittal view of the human brain: Click on the words to learn what these structures do: THE BRAIN FROM TOP TO BOTTOM Human memory is a complex phenomenon, however, and of course involves other regions of the brain as well . Though the hippocampus is an essential brain structure for the proper functioning of long-term memory, it cannot be regarded as the “memory centre” in the same sense that the occipital cortex, for example, can be regarded as the centre for processing visual information. The reason is that long-term memory is not located in just one specific area of the brain. The hippocampus is the catalyst for long-term memory, but the actual memory traces are encoded at various places in the cortex. The destruction of both hippocampi (as the result of a stroke, for example) has disastrous effects on long-term memory, preventing the individual from learning anything new whatsoever. The most important evidence of the role of the hippocampus in transferring long-term memories has been provided by subjects who had sustained damage to both hippocampi and could not keep things in their memories for more than a few moments.

LONG-TERM MEMORY Information is transferred from short-term memory (also known as working memory) to long-term memory through the hippocampus, so named because its shape resembles the curved tail of a seahorse (hippokampos in Greek). The hippocampus is a very old part of the cortex, evolutionarily, and is located in the inner fold of the temporal lobe. All of the pieces of information decoded in the various sensory areas of the cortex converge in the hippocampus, which then sends them back where they came from. The hippocampus is a bit like a sorting centre where these new sensations are compared with previously recorded ones. The hippocampus also creates associations among an object’s various properties. When we remember new facts by repeating them or by employing various mnemonic devices , we are actually passing them through the hippocampus several times. The hippocampus keeps strengthening the associations among these new elements until, after a while, it no longer needs to do so. The cortex will have learned to associate these various properties itself to reconstruct what we call a memory.

Source: Collection of Carol Donner Brain Anatomy, Anatomy of the Human Brain Anatomy of the Brain Overview The brain is an amazing three-pound organ that controls all functions of the body, interprets information from the outside world, and embodies the essence of the mind and soul. Intelligence, creativity, emotion, and memory are a few of the many things governed by the brain. Protected within the skull, the brain is composed of the cerebrum, cerebellum, and brainstem. The brainstem acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. The brain receives information through our five senses: sight, smell, touch, taste, and hearing - often many at one time. It assembles the messages in a way that has meaning for us, and can store that information in our memory. The brain controls our thoughts, memory and speech, movement of the arms and legs, and the function of many organs within our body. It also determines how we respond to stressful situations (such as taking a test, losing a job, or suffering an illness) by regulating our heart and breathing rate. Nervous system The nervous system is divided into central and peripheral systems.

The central nervous system (CNS) is composed of the brain and spinal cord. The peripheral nervous system (PNS) is composed of spinal nerves that branch from the spinal cord and cranial nerves that branch from the brain. The PNS includes the autonomic nervous system, which controls vital functions such as breathing, digestion, heart rate, and secretion of hormones. Skull The purpose of the bony skull is to protect the brain from injury. The skull is formed from 8 bones that fuse together along suture lines. These bones include the frontal, parietal (2), temporal (2), sphenoid, occipital and ethmoid (Fig. 1). The face is formed from 14 paired bones including the maxilla, zygoma, nasal, palatine, lacrimal, inferior nasal conchae, mandible, and vomer. Figure 1. Eight bones form the skull and fourteen bones form the face. Inside the skull are three distinct areas: anterior fossa, middle fossa, and posterior fossa (Fig. 2). Doctors sometimes refer to a tumor’s location by these terms, e.g., middle fossa meningioma. Figure 2.

The inside of the skull is divided into three areas called the anterior, middle, and posterior fossae. Similar to cables coming out the back of a computer, all the arteries, veins and nerves exit the base of the skull through holes, called foramina. The big hole in the middle (foramen magnum) is where the spinal cord exits. Brain The brain is composed of the cerebrum, cerebellum, and brainstem (Fig. 3). Figure 3. The brain is composed of three parts: the brainstem, cerebellum, and cerebrum. The cerebrum is divided into four lobes: frontal, parietal, temporal, and occipital. The cerebrum is the largest part of the brain and is composed of right and left hemispheres. It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement. The cerebellum is located under the cerebrum. Its function is to coordinate muscle movements, maintain posture, and balance. The brainstem includes the midbrain, pons, and medulla. It acts as a relay center connecting the cerebrum and cerebellum to the spinal cord.

It performs many automatic functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing. Ten of the twelve cranial nerves originate in the brainstem. The surface of the cerebrum has a folded appearance called the cortex. The cortex contains about 70% of the 100 billion nerve cells. The nerve cell bodies color the cortex grey-brown giving it its name – gray matter (Fig. 4). Beneath the cortex are long connecting fibers between neurons, called axons, which make up the white matter. Figure 4. The surface of the cerebrum is called the cortex. The cortex contains neurons (grey matter), which are interconnected to other brain areas by axons (white matter). The cortex has a folded appearance. A fold is called a gyrus and the groove between is a sulcus. The folding of the cortex increases the brain’s surface area allowing more neurons to fit inside the skull and enabling higher functions. Each fold is called a gyrus, and each groove between folds is called a sulcus. There are names for the folds and grooves that help define specific brain regions.

Right brain – left brain The right and left hemispheres of the brain are joined by a bundle of fibers called the corpus callosum that delivers messages from one side to the other. Each hemisphere controls the opposite side of the body. If a brain tumor is located on the right side of the brain, your left arm or leg may be weak or paralyzed. Not all functions of the hemispheres are shared. In general, the left hemisphere controls speech, comprehension, arithmetic, and writing. The right hemisphere controls creativity, spatial ability, artistic, and musical skills. The left hemisphere is dominant in hand use and language in about 92% of people. Lobes of the brain The cerebral hemispheres have distinct fissures, which divide the brain into lobes. Each hemisphere has 4 lobes: frontal, temporal, parietal, and occipital (Fig 3). Each lobe may be divided, once again, into areas that serve very specific functions. It’s important to understand that each lobe of the brain does not function alone. There are very complex relationships between the lobes of the brain and between the right and left hemispheres.

Frontal lobe Hearing Sequencing and organization Messages within the brain are carried along pathways. Messages can travel from one gyrus to another, from one lobe to another, from one side of the brain to the other, and to structures found deep in the brain (e.g. thalamus, hypothalamus). Deep structures Hypothalamus - is located in the floor of the third ventricle and is the master control of the autonomic system. It plays a role in controlling behaviors such as hunger, thirst, sleep, and sexual response. It also regulates body temperature, blood pressure, emotions, and secretion of hormones. Pituitary gland - lies in a small pocket of bone at the skull base called the sella turcica. The pituitary gland is connected to the hypothalamus of the brain by the pituitary stalk. Known as the “master gland,” it controls other endocrine glands in the body. It secretes hormones that control sexual development, promote bone and muscle growth, respond to stress, and fight disease. Pineal gland - is located behind the third ventricle. It helps regulate the body’s internal clock and circadian rhythms by secreting melatonin. It has some role in sexual development.

Thalamus - serves as a relay station for almost all information that comes and goes to the cortex (Fig. 5). It plays a role in pain sensation, attention, alertness and memory. Figure 5. Coronal cross-section showing the basal ganglia. Basal ganglia - includes the caudate, putamen and globus pallidus. These nuclei work with the cerebellum to coordinate fine motions, such as fingertip movements. Limbic system - is the center of our emotions, learning, and memory. Included in this system are the cingulate gyri, hypothalamus, amygdala (emotional reactions) and hippocampus (memory). Cranial nerves The brain communicates with the body through the spinal cord and twelve pairs of cranial nerves (Fig. 6). Ten of the twelve pairs of cranial nerves that control hearing, eye movement, facial sensations, taste, swallowing and movement of the face, neck, shoulder and tongue muscles originate in the brainstem. The cranial nerves for smell and vision originate in the cerebrum. Figure 6. The Roman numeral, name, and main function of the twelve cranial nerves.

moves tongue Meninges The brain and spinal cord are covered and protected by three layers of tissue called meninges. From the outermost layer inward they are: the dura mater, arachnoid mater, and pia mater. The dura mater is a strong, thick membrane that closely lines the inside of the skull; its two layers, the periosteal and meningeal dura, are fused and separate only to form venous sinuses. The dura creates little folds or compartments. There are two special dural folds, the falx and the tentorium. The falx separates the right and left hemispheres of the brain and the tentorium separates the cerebrum from the cerebellum. The arachnoid mater is a thin, web-like membrane that covers the entire brain. The arachnoid is made of elastic tissue. The space between the dura and arachnoid membranes is called the subdural space. The pia mater hugs the surface of the brain following its folds and grooves. The pia mater has many blood vessels that reach deep into the brain. The space between the arachnoid and pia is called the subarachnoid space.

It is here where the cerebrospinal fluid bathes and cushions the brain. Ventricles and cerebrospinal fluid The brain has hollow fluid-filled cavities called ventricles (Fig. 7). Inside the ventricles is a ribbon-like structure called the choroid plexus that makes clear colorless cerebrospinal fluid (CSF). CSF flows within and around the brain and spinal cord to help cushion it from injury. This circulating fluid is constantly being absorbed and replenished. Figure 7. CSF is produced inside the ventricles deep within the brain. CSF fluid circulates inside the brain and spinal cord and then outside to the subarachnoid space. Common sites of obstruction: 1) foramen of Monro, 2) aqueduct of Sylvius, and 3) obex. There are two ventricles deep within the cerebral hemispheres called the lateral ventricles. They both connect with the third ventricle through a separate opening called the foramen of Monro. The third ventricle connects with the fourth ventricle through a long narrow tube called the aqueduct of Sylvius.

From the fourth ventricle, CSF flows into the subarachnoid space where it bathes and cushions the brain. CSF is recycled (or absorbed) by special structures in the superior sagittal sinus called arachnoid villi. A balance is maintained between the amount of CSF that is absorbed and the amount that is produced. A disruption or blockage in the system can cause a build up of CSF, which can cause enlargement of the ventricles (hydrocephalus) or cause a collection of fluid in the spinal cord (syringomyelia). Blood supply Blood is carried to the brain by two paired arteries, the internal carotid arteries and the vertebral arteries (Fig. 8). The internal carotid arteries supply most of the cerebrum. Figure 8. The common carotid artery courses up the neck and divides into the internal and external carotid arteries. The brain’s anterior circulation is fed by the internal carotid arteries (ICA) and the posterior circulation is fed by the vertebral arteries (VA). The two systems connect at the Circle of Willis (green circle). The vertebral arteries supply the cerebellum, brainstem, and the underside of the cerebrum.

After passing through the skull, the right and left vertebral arteries join together to form the basilar artery. The basilar artery and the internal carotid arteries “communicate” with each other at the base of the brain called the Circle of Willis (Fig. 9). The communication between the internal carotid and vertebral-basilar systems is an important safety feature of the brain. If one of the major vessels becomes blocked, it is possible for collateral blood flow to come across the Circle of Willis and prevent brain damage. Figure 9. Top view of the Circle of Willis. The internal carotid and vertebral-basilar systems are joined by the anterior communicating and posterior communicating arteries. The venous circulation of the brain is very different than the rest of the body. Usually arteries and veins run together as they supply and drain specific areas of the body. So one would think there would be a pair of vertebral veins and internal carotid veins. However, this is not the case in the brain. The major vein collectors are integrated into the dura to form venous sinuses (Fig. 10) - not to be confused with the air sinuses in the face and nasal region.

The venous sinuses collect the blood from the brain and pass it to the internal jugular veins. The superior and inferior sagittal sinuses drain the cerebrum, the cavernous sinuses drains the anterior skull base. All sinuses eventually drain to the sigmoid sinuses, which exit the skull and form the jugular veins. These two jugular veins are essentially the only drainage of the brain. Figure 10. Three quarter view of the dural covering of the brain depicts the two major dural folds, the falx and tentorium along with the venous sinuses. Language In general, the left hemisphere of the brain is responsible for language and speech and is called the "dominant" hemisphere. The right hemisphere plays a large part in interpreting visual information and spatial processing. In about one third of individuals who are left-handed, speech function may be located on the right side of the brain. Left-handed individuals may need special testing to determine if their speech center is on the left or right side prior to any surgery in that area. Aphasia is a disturbance of language affecting production, comprehension, reading or writing, due to brain injury – most commonly from stroke or trauma. The type of aphasia depends on the brain area affected.

Broca’s area lies in the left frontal lobe (Fig 3). If this area is damaged, one may have difficulty moving the tongue or facial muscles to produce the sounds of speech. The individual can still read and understand spoken language but has difficulty in speaking and writing (i.e. forming letters and words, doesn't write within lines) – called Broca's aphasia. Wernicke's area lies in the left temporal lobe (Fig 3). Damage to this area causes Wernicke's aphasia. The individual may speak in long sentences that have no meaning, add unnecessary words, and even create new words. They can make speech sounds, however they have difficulty understanding speech and are therefore unaware of their mistakes. Memory Memory is a complex process that includes three phases: encoding (deciding what information is important), storing, and recalling. Different areas of the brain are involved in memory depending on the type of memory. Short-term memory, also called working memory, occurs in the prefrontal cortex. It stores information for about one minute and its capacity is limited to about 7 items. For example, it enables you to dial a phone number someone just told you.

It also intervenes during reading, to memorize the sentence you have just read, so that the next one makes sense. Long-term memory is processed in the hippocampus of the temporal lobe and is activated when you want to memorize something for a longer time. This memory has unlimited content and duration capacity. It contains personal memories as well as facts and figures. Skill memory is processed in the cerebellum, which relays information to the basal ganglia. It stores automatic learned memories like tying a shoe, playing an instrument, or riding a bike. Cells of the brain The brain is made up of two types of cells: nerve cells (neurons) and glia cells. Nerve cells There are many sizes and shapes of neurons, but all consist of a cell body, dendrites and an axon. The neuron conveys information through electrical and chemical signals. Try to picture electrical wiring in your home. An electrical circuit is made up of numerous wires connected in such a way that when a light switch is turned on, a light bulb will beam. A neuron that is excited will transmit its energy to neurons within its vicinity. Neurons transmit their energy, or “talk”, to each other across a tiny gap called a synapse (Fig.

11). A neuron has many arms called dendrites, which act like antennae picking up messages from other nerve cells. These messages are passed to the cell body, which determines if the message should be passed along. Important messages are passed to the end of the axon where sacs containing neurotransmitters open into the synapse. The neurotransmitter molecules cross the synapse and fit into special receptors on the receiving nerve cell, which stimulates that cell to pass on the message. Figure 11. Nerve cells consist of a cell body, dendrites and axon. Neurons communicate with each other by exchanging neurotransmitters across a tiny gap called a synapse. Glia cells Glia (Greek word meaning glue) are the cells of the brain that provide neurons with nourishment, protection, and structural support. There are about 10 to 50 times more glia than nerve cells and are the most common type of cells involved in brain tumors. Astroglia or astrocytes transport nutrients to neurons, hold neurons in place, digest parts of dead neurons, and regulate the blood brain barrier. Oligodendroglia cells provide insulation (myelin) to neurons.

Ependymal cells line the ventricles and secrete cerebrospinal fluid (CSF). Microglia digest dead neurons and pathogens. Sources & links If you have more questions, please contact Mayfield Brain & Spine at 800-325-7787 or 513-221-1100. Links updated > 4.2016 reviewed by > Tonya Hines, CMI, Mayfield Clinic / University of Cincinnati Department of Neurosurgery, Ohio Mayfield Certified Health Info materials are written and developed by the Mayfield Clinic. We comply with the HONcode standard for trustworthy health information. This information is not intended to replace the medical advice of your health care provider. Mayfield services During the past 10 to 15 years medical science has made a quantum leap in our understanding of the human brain and spinal cord. These revelations have been fueled by advances in imaging technology and neurobiology. Whether they are studying genetic biomarkers in basic science laboratories or perusing functional MRI scans at an advanced imaging center, Mayfield researchers are making new discoveries about how nerve cells work, grow, die, and repair themselves.

Every day, we are working to translate new research discoveries into better treatments for our patients. Learn more about our brain research at the UC Department of Neurosurgery. To make an appointment call 513-221-1100. Where Are Old Memories Stored in the Brain? - Scientific American Scientific American Mind Where Are Old Memories Stored in the Brain? A new study suggests that the location of a recollection in the brain varies based on how old that recollection is By Moheb Costandi on February 10, 2009 Advertisement | Report Ad In the 1920s the behavioral psychologist Karl Lashley conducted a now famous series of experiments in an attempt to identify the part of the brain in which memories are stored. He trained rats to find their way through a maze, then made lesions in different parts of the cerebral cortex in an attempt to erase what he called the "engram," or the original memory trace. Lashley failed to find the engram—his experimental animals were still able to find their way through the maze, no matter where he put lesions on their brains. He therefore concluded that memories are not stored in any single area of the brain, but are instead distributed throughout it.

Subsequent work on amnesics—most notably the studies of the recently deceased patient known only as H.M. carried out by Brenda Milner—implicated a part of the brain called the hippocampus as being crucial for memory formation. More recently, it was established that the frontal cortex is also involved; current thinking holds that new memories are encoded in the hippocampus and then eventually transferred to the frontal lobes for long-term storage. A new study , led by Christine Smith and Larry Squire at the University of California at San Diego, now provides evidence that the age of a memory determines the extent to which we are dependent on the frontal cortex and hippocampus for recalling it. In other words, the location of a recollection in the brain varies based on how old that recollection is. Smith and Squire assessed the brain activity associated with the recollection of old and new memories . They recruited 15 healthy male participants, and used functional magnetic resonance imaging (fMRI) to scan their brains while they answered 160 questions about news events that took place at different periods of time during the past 30 years.

The study sounds simple, but the design of the experiments was actually somewhat complex, because the researchers had to overcome a number of confounding variables. First, when one is asked to recall any given memory, the brain encodes not only the questions that were asked to cue the retrieval, but also the resulting recollection, so the associated activity could therefore interfere with that which is being assessed. Second, more recent memories are likely to be richer and more vivid than older ones, so the strength of the fMRI signal could be related not just to the time at which a recalled event occurred but also to the richness of the participants' recollection of it. Finally, recalled memories could be strongly associated with personal events in the participants' lives, which could make them easier to remember. Testing Old Memories Smith and Squire therefore designed their experiments so that they could assess the effects of the age of a memory independently of both the encoding of the test questions and richness of the recollection of the memory. At the beginning of the task, the researchers presented in random order blocks of questions about events in each time period, and they asked participants to indicate whether or not they knew the answer.

About 10 minutes later, while still in the scanner, the participants were asked three questions about each news event. First, they were asked to recall the original question they had been asked about the event (to assess how well they had encoded the information). Then, they were asked the answer to that question (to assess the accuracy of recall) and, finally, how much they knew about each of the events (to assess the richness of each memory). In general, the participants' ability to recall any given news event decreased in relation to the amount of time that had passed since the event had occurred. As expected, they were better able to recollect more recent events than older ones. The researchers also found that the participants' memory of the questions they had been asked, and of the content of each news event, was independent of how long ago the events had occurred. The richness of the participants' memories was also unrelated to when a particular event occurred; the memories of events that occurred in the distant past were often as rich as those of more recent events. In their analyses, the researchers used only those fMRI data from the questions that had been answered correctly.

This data set showed that medial temporal lobe structures (the hippocampus and amygdala) exhibited gradually decreasing activity as the participants recalled progressively older memories. This drop in activity was true for memories of news events that occurred up to 12 years before, but the recollection of events that took place longer than 12 years was associated with a constant level of activity in those areas. The opposite activation pattern was observed in areas of the frontal, parietal and lateral temporal lobes: activity in these areas increased with the age of the news event being recalled, but remained constant during the recollection of more recent events. File Cabinets in the Brain This study therefore provides anatomical and functional evidence supporting the findings obtained from brain-damaged patients with memory impairments. Patients such as H.M., who have lesions in the hippocampus on both sides of the brain, not only lose the ability to form new memories, but also lose memories for events that occurred in the years preceding the onset of their amnesia. The memories of events that took place in the distant past remain intact , whereas those that occurred at intermediate times are lost in a graded manner.

This finding suggests that, with time, the hippocampus becomes less important for a given memory, and the frontal cortex more so. Lashley's theory of memory was not right, but neither was it completely wrong. Why, then, might old memories be transferred from the hippocampus to the frontal cortex? It may be because retrieving older memories requires stronger associations and increased effort—memory encoding in the frontal cortex is more complex than in the hippocampus, and involves a widely distributed network with a greater number of connections. The frontal cortex may therefore be better suited to the task of retrieving memories that were encoded in the distant past. Are you a scientist? Have you recently read a peer-reviewed paper that you want to write about? Then contact Mind Matters editor Jonah Lehrer , the science writer behind the blog The Frontal Cortex and the book Proust Was a Neuroscientist . His latest book is How We Decide . Emotions | UCSF Memory and Aging Center UCSF Memory and Aging Center Print Article Download PDF Emotional and behavioral symptoms are common in dementia and can be major sources of stress to patients and their caregivers.

Some of the most common emotional and behavioral changes associated with dementia are: Apathy and Indifference—lack of motivation to start new activities and continue old ones, reduced participation in household chores, loss of interest in talking to other people, becoming less affectionate and emotionally expressive. Depression and Dysphoria—tearfulness and crying, consistently low mood, feelings of failure, despair about the future, suicidal thoughts and actions. Disinhibition—acting impulsively without thinking, saying or doing things not usually done or said in public, doing things that are embarrassing to others. Euphoria and Elation—inappropriate giggling and laughter, playing childish games, feeling excessively good for no apparent reason, making false claims about one’s abilities or wealth. Anxiety—being nervous or worried for no reason, avoiding situations that cause nervousness, tenseness or shortness of breath with no other explanation. Irritability and Lability—increased temper, crankiness, rapid mood changes. Agitation and Aggression—resisting those trying to help, refusing to cooperate, stubbornness, yelling, hitting. Eating Disorders—changes in weight (gain or loss), changes in appetite, changes in appropriate eating behavior, preferences for only certain types of foods.

Sleep Disturbances—difficulty falling asleep or staying asleep, wandering or pacing in the middle of the night, getting up and getting dressed. Aberrant Motor Behaviors—repetitive behaviors such as opening and closing doors or drawers, repeatedly picking at things, pacing back and forth. Hallucinations—seeing or hearing things that do not exist. Delusions—holding false beliefs, such as thinking family members are not who they say they are, that others intend one harm, or that one’s home is not his/her home. Anatomy of Emotion and Behavior Emotional and behavioral symptoms are thought to be caused by damage to specific areas of the brain that are responsible for directing our attention, motivating our behavior, and learning the significance of what is going on around us. Pioneering work by Papez (1937) originally suggested that emotion is related to a ring of structures in the center of the brain called the limbic system. This ring includes the hypothalamus, anterior thalamic nuclei, cingulate cortex, and hippocampus. More recent research has shown that some of these structures are not as directly related to emotion as others, while additional structures have also been added to the list.

The following brain structures are currently thought to be most involved in emotion and behavior: Amygdala—The amygdalae are two small round structures located near the anterior (front) end of the temporal lobes. The amygdalae are involved in detecting and learning what parts of our surroundings are important and have emotional significance. They are critical for the production of emotion and may be particularly important for the generation of negative emotions, especially fear. Prefrontal Cortex—The term prefrontal cortex refers to the very front part of the brain located behind the forehead and above the eyes. It appears to play a critical role in the regulation of emotion and behavior by anticipating the consequences of our actions. The prefrontal cortex may play an important role in delayed gratification by maintaining emotions over time and organizing our behavior toward specific goals. Anterior Cingulate—The anterior cingulate cortex (ACC) is located in the middle of the brain just behind the prefrontal cortex. The ACC is thought to play a central role in attention, and may be particularly important with regard to one’s conscious subjective emotional awareness. This region of the brain may also play an important role in the initiation of motivated behavior.

Ventral Striatum—The ventral striatum refers to a group of subcortical structures thought to play an important role in emotion and behavior. One part of the ventral striatum called the nucleus accumbens is thought to be involved in the experience of goal-directed positive emotion. Individuals with addictions, for example, experience increased activity in this area when they encounter the object of their addiction. Insula—The insular cortex is thought to play a critical role in the bodily experience of emotion, as it is connected to other brain structures that regulate the body’s autonomic functions (heart rate, breathing, digestion, etc.). This region also processes taste information and is thought to play an important role in experiencing the emotion of disgust. Impact of Neurologic Illness on Emotion and Behavior Neurologic disorders result in different patterns of emotional and behavioral changes depending on what parts of the brain are affected. In frontotemporal dementia, behavioral and emotional changes are often dramatic and form the core clinical features of the disorder. In other disorders, behavioral and emotional changes may occur, but are often less common or less severe.

Frontotemporal Dementia (FTD)—FTD is associated with atrophy of the prefrontal cortex, anterior cingulate, insula, and ventral striatum. When this atrophy is predominantly right-sided, FTD is almost always associated with changes in behavioral and emotional function. The changes most commonly associated with FTD are apathy, disinhibition, aberrant motor behaviors and eating disorders (specifically increases in appetite and strong preferences for sweets or other particular foods). Other behavioral changes in FTD include elation and euphoria, aggression, irritability, sleep disturbances, depression, and anxiety. Sometimes patients with FTD also develop addictive behaviors late in life. Semantic Dementia (SD)—SD results from atrophy of the anterior temporal lobes (including the amygdala), insula, prefrontal cortex, and anterior cingulate. Though more commonly thought of as a language disorder, SD is often associated with dramatic changes in behavioral and emotional function. Disinhibition and compulsive behaviors are the most common changes in SD. Other common changes include apathy, eating disorders, sleep disturbances, elation and euphoria, as well as depression, anxiety, irritability, and aggression.

Alzheimer's Disease (AD)—The behavioral and emotional changes seen in AD, on average, are less severe than those that occur in FTD and SD particularly in the early stages. The most common behavioral change associated with AD is apathy. Also common in AD are irritability, agitation, depression, anxiety, sleep disturbances, and eating disorders (especially a decreased appetite and loss of weight). Dementia With Lewy Bodies (DLB)—DLB may be associated with many of the same changes seen in AD. DLB is often associated with vivid hallucinations (such as small children or animals). Other Disorders—Behavioral and emotional changes are less common or less severe in disorders such as corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), primary progressive aphasia (PPA) and progressive nonfluent aphasia (PNFA). Brain Parts Function & Parts of the Brain Brain Function, It's a Team Sport The brain is the most complex organ in the body. It is the organ that allows us to think, have emotions, move, and even dream. Given this complexity, it should not be surprising that there are many ways to separate the parts of the brain.

Brain parts can be separated on the basis of what they look like to the naked eye, under a microscope, or by what certain brain parts do. The brain and spinal cord make up the central nervous system and all of the nerves found in our body make up the peripheral nervous system. When you see a picture of the brain you probably think of a wrinkled gray blob. Well, the wrinkles are called cortex and it is where the majority of brain cells or neurons reside. The cortex can be divided into four main lobes. The frontal lobe, where you do your heavy thinking, pondering and planning your actions; temporal cortex, where you process sounds and form memories; occipital cortex, where you process all the things that you see; and parietal cortex, where you integrate or makes sense of all of the different bits of information that are bombarding your brain. The Hindbrain Having evolved hundreds of millions of years ago, the Hindbrain or the Reptillian Brain is the oldest part of the human brain. As you might guess from it's name, it's a piece of brain anatomy that we share with reptiles and is the most primitive. Likewise it's in charge of our primal instincts and most basic functions.

Things like the instincts of survival, dominance, mating and the basic functions of respiration, heartbeat all come from this area of the brain. Located in the Hindbrain are: The Spinal Cord This is the infomation superhighway of the body. It carries information up to the brain and instructions back down. The Medulla Oblongata Helps control the body's autonomic functions (things you don't need to think about to perform) like respiration, digestion and heart rate. Also acts as a relay station for nerve signals going to/from the brain The Pons Has roles in your level of arousal or conciousness and sleep. Relays sensory information to/from the brain. Also involved in controlling autonomic body functions. The Cerebellum Mostly deals with movement. It regulates and coordinates movement, posture and balance. Also involved in learning movement. The Limbic System The Limbic System sometimes called the "emotional brain" or "Old Mammalian Brain" is the next part of the brain to have evolved in the more primitive mammals about 150 million years ago. This is where our emotions reside, where memory begins and where these two functions combine together to mark behaviours with positive or negative feelings.

It's where mostly unconcious value judgements are made. Information going through the Limbic System are filed under "agreeable or disagreeable". It also plays a role in salience (what grabs your attention), spontaneity and creativity. Located in the Limbic System are: The Amygdala It's name is latin for almond which relates to its shape. It helps in storing and classifying emotionally charged memories. It plays a large role in producing our emotions, especially fear. It's been found to trigger responses to strong emotion such as sweaty palms, freezing, increased heart-beat/respiration and stress hormone release. The Hippocampus This guy is all about memory and a little about learning. It's primary role is in memory formation, classifying information, long-term memory. Like the RAM in your computer it processes and stores new and temporary memory for long term storage. It's also involved in interpreting incoming nerve signals and spatial relationships. The Hypothalamus It should be called the Hyperthalamus because it does so much. It's linked closely with the pituitary gland to control many of the body's functions.

It monitors and controls your circadian rhythms (your daily sleep/wake cycle), homeostasis (making sure your body is running smoothly), apetite, thirst, other bodily urges and also plays a role in emotions, autonomic functions and motor functions. The Thalamus The Thalamus is THE relay station in the brain. Most of the sensory signals, auditory (sound), Visual, Somatosensory (from your skin and internal organs), go through this organ on their way to other parts of the brain for processing. It also plays a function in motor control. The Neocortex The last and most advanced brain to evolve to date is called the Neocortex, neomammalian or rational brain. We share this part of our brain with other higher level mammals like the primates and dolphins, although in humans the neocortex is the largest. It takes up 2/3's of the human brain. This is where we find the brain power to develop language, abstract thought, conciousness and imagination. Let there be no doubt, this is what grants us our status on the food chain and allows us to be human. The Neocortex is divided into two hemispheres, right and left.

The right side of the brain controls the left side of the body and vice versa. Also the hemispheres are divided in terms of what kind of thought they process or produce. The right being more concerned with the artistic, spatial and musical. While the left is more concerned with the colder, linear, rational and verbal aspects. Located in the Neocortex are: The Frontal Lobe This is the most recent evolutionary addition to the brain. If the brain had a White House it would be here. It is the true center for command and control in your body. The Frontal lobe is responsible for functions such as reasoning, problem solving, judgement, impulse control. This coupled with the fact that it's the last to develop when we are young adults, probably answers a lot of questions for many parents out there. It also manages our higher emotions such as empathy and altruism. This lobe is also involved in motor control and memory. The Parietal Lobe The Parietal Lobe is involved in processing pain and touch sensation. It's where the Somatosensory (from your skin and internal organs) Cortex resides. It's also associated with cognition (including calculating location and speed of objects), movement, orientation, recognition and speech.

The Temporal Lobe The Temporal Lobe is involved in auditory (sound) sensation and is where the Primary Auditory Cortex and on the left hemisphere, Wernicke's Area (language recognition) are located. This lobe is also involved in emotion, memory and speech. The Occipital Lobe

Question: What part of the brain is predominantly associated with memory?
Answer: HIPPOCAMPUS